Tool unit of a rotary swaging machine

ABSTRACT

The invention relates to a tool unit of a rotary swaging machine for shaping preferably rod-like or pipe-like workpieces. The tool unit has a plurality of shaping tools ( 22 ) which are arranged about an operating axis ( 18 ) and which can be driven radially relative to the operating axis ( 18 ) with a stroke movement by means of a tool drive. There are associated with the shaping tools adjustment means ( 38 ), by which stroke positions of the shaping tools ( 22 ) are adjustable in such a manner that the shaping tools ( 22 ) abut each other with a closing pressure which is dependent on the stroke positions adjusted when the shaping tools ( 22 ) are in a closed state. According to the invention, the tool unit has a measuring device for measuring a parameter, by means of which the closure pressure produced at the adjusted stroke positions of the shaping tools ( 22 ) can be verified.

The invention relates to a tool unit of a rotary swaging machine for shaping preferably rod-like or pipe-like workpieces, having a plurality of shaping tools which are arranged about an operating axis and which can be driven radially relative to the operating axis with a stroke movement by means of a tool drive, and having adjustment means, by which stroke positions of the shaping tools are adjustable in such a manner that the shaping tools abut each other with a closing pressure which is dependent on the stroke positions adjusted when the shaping tools are in a closed state.

Such tool units have been used in practice for a long time to shape rod-like or pipe-like workpieces, in which a defined workpiece longitudinal portion is generally reduced in terms of its cross-section.

To that end, the tool units have in principle at least two shaping tools which can completely or partially surround the workpiece longitudinal portion to be processed and which are simultaneously moved radially relative to each other towards the workpiece longitudinal portion with a high-frequency oscillating movement in order to shape the workpiece and apply thereto high radial pressing forces. During the shaping operation, there is further produced a relative rotational movement between the workpiece and the shaping swaging tools so that the workpiece longitudinal portion is acted on with pressure uniformly over the entire periphery thereof by the shaping swaging tools.

In the case of rotary swaging, a distinction is drawn substantially between a so⁻called feed and a plunge-cut rotary swaging method, the swaging method being used being determined by the workpiece geometry to be produced.

In this regard, the feed method is distinguished by constantly adjusted stroke positions of the shaping tools, that is to say, radial stroke end positions of the shaping tools remaining constant relative to the operating axis of the tool units during processing.

On the other hand, the stroke positions of the shaping tools are changed in the case of plunge-cut rotary swaging by the tools being opened or closed in a radial and controlled manner so as to be superimposed on the actual radial oscillation of the shaping tools.

In principle, the result of the shaping operation depends decisively on the shaping tools having correctly adjusted stroke positions. In the case of (numerically controlled) plunge-cut rotary swaging, for example, the stroke positions of the shaping tools at which the shaping tools abut each other with a closing pressure dependent on the stroke positions adjusted when the shaping tools are in a closed state, the so-called closure point, are used as a reference value for controlling the workpiece shaping operations.

In practice, in order to adjust the closure point, the stroke positions of the shaping tools are adjusted with simultaneous manual driving of the shaping tools gradually in the direction towards the operating axis of the tool unit (so-called jog operation) until the stroke positions of the shaping tools are adjusted in such a manner that an operator accepts, on the basis of the force application necessary for manually driving the shaping tools, that there is adjusted a correct closure point, that is to say, a closure point which is desired for a subsequent workpiece shaping operation.

This operation involves the risk of adjusting the closure point with excessively high closure pressure so that damage may occur to the machine tool during operation of the tool unit.

Therefore, an object of the invention is to provide a tool unit according to the preamble of claim 1 and an adjustment method of a tool unit according to the invention which have a reduced risk of overloading components of the tool unit and associated damage.

The object is achieved according to the invention by a tool unit having the features set out in claim 1. The object relating to the adjustment method is achieved by a method having the features set out in claim 12.

According to the invention, there is provided in the tool unit mentioned in the introduction a measuring device for measuring a parameter, by means of which the closure pressure produced at the adjusted stroke positions of the shaping tools can be verified. It is thereby possible, on the one hand, to adjust the stroke positions of the shaping tools of the tool unit readily and in a reproducible manner so that a defined closure pressure is provided or complied with at the closure point of the shaping tools. The risk of overloading of the components of the tool unit and consequently damage thereto is thereby minimised. The adjustment of the tool unit is further simplified and can also be carried out by a less experienced operator. It is further, possible to achieve weaker tolerance deviations of the shaping products owing to the objectified and reproducible adjustment of the closure point, which is particularly advantageous in the production of highly precise components with narrow tolerances.

Other advantageous construction types of the invention according to claim 1 will be appreciated from the features of dependent claims 2 to 11 and another advantageous construction type of the invention according to claim 12 will be appreciated from the features of dependent claim 13.

A particularly preferred development of the invention is distinguished in that a control unit is provided for closure pressure control, it being possible to process the measured parameter for verifying the closure pressure by means of the control unit, in particular in relation to a desired range or desired value setting.

The associated advantage substantially consists in that the adjustment of the tool unit is simplified. For instance, measurement values of the measuring device can be provided in the simplest case in such a manner that they can be made accessible to the operator, for example, by a display unit. In that case, it is further necessary for the user to verify the closure pressure, for example, by means of corresponding tables, with which the operator is capable of associating a corresponding closure pressure with the measurement value. In the advantageous case of reference to a desired range or a desired value setting, there can be provided by the control unit information which is based on an evaluation of the measurement values of the parameter. That information may provide, for example, an indication of excessively low, correct or excessively high closure pressure adjustment and be made accessible to the user by means of an acoustic or optical display. The adjustment of the tool unit is thereby substantially simplified generally and the operating comfort increased. The risk of mal-adjustment and associated damage to the tool unit is further minimised at the same time.

The tool unit preferably has an operating mode, which can be selected via the control unit, in order to verify the closure pressure. This affords the advantage that the risk of overloading the tool unit and associated damage is reduced. The shaping tools can particularly be moved selectively as far as the closure point and retained therein. However, the shaping tools are preferably driven with a number of strokes sufficiently low for reliably measuring the parameter, whereby it is also possible to take into consideration, at least partially, dynamic effects occurring during driving of the shaping tools.

The drive can be provided according to the invention in order to produce a relative rotational movement of a tool holder and an external ring which engages round the tool holder, whereby there is produced a construction type of the tool unit that is particularly robust and not very liable to malfunctions during operation.

According to a preferred development of the invention, the measuring device is provided for measuring a parameter, by means of which a drive torque for driving the shaping tools can be established. On the one hand, this allows, a structurally particularly simple construction of the measuring device because it is not necessary to have a plurality of measurement sensors which are associated with the shaping tools, respectively. Establishing the drive torque further allows reliable verification (totalled over the shaping tools) of the closure pressure of the shaping tools because it results from the drive torque of the tool drive introduced into the shaping tools and is proportional thereto. Furthermore, overloading the drive train can also particularly be prevented by establishing the drive torque.

From a structural viewpoint, it has been found to be advantageous for the measuring device to be provided for measuring the consumption of electrical current of the tool drive when the shaping tools are driven. The input current of the tool drive has a close correlation, on the one hand, to the (electrical) power consumption of the tool drive and, on the other hand, to the drive torque which is applied by the tool drive and therefore allows simple and reliable establishment of those characteristic values. Using those characteristic values, the closure pressure of the shaping tools derived from the drive torque of the tool drive can be established without excessive complexity. Such a measuring device is further substantially insensitive to the vibrations which occur during operation of the tool unit and offer a cost advantage owing to their free commercial availability, for example, relative to other more complex devices for establishing the drive torque.

In the case of establishing the closure pressure indirectly by means of the power consumption of the tool unit, the measuring device preferably further detects an operating voltage which is applied to the tool drive and by means of which the power consumption can be established by calculation.

The closure pressure can preferably be determined by the control unit using a characteristic line, which is preferably defined in the control unit, for the parameter or a characteristic value determined by means of the parameter and the closure pressure. The characteristic line describes the relationship between the measured parameter or a characteristic value determined by means of the parameter and the closure pressure of the shaping tools and can be stored in the control unit in tabular form or in the form of a mathematical formula.

According to an embodiment of the invention, the adjustment means are in the form of a plurality of adjustment wedges which are preferably guided between the shaping tools and swaging rams associated therewith and which are arranged parallel with the operating axis, the adjustment wedges being longitudinally displaceable in the direction towards the operating axis relative to the shaping tools in order to adjust the stroke positions of the shaping tools. Particularly robust stroke position adjustment which is insensitive to disruptive influences is thereby possible even during the shaping operation.

According to the invention, the adjustment means can preferably be adjusted together and, to that end, are connected in particular to a positioning means, for example, a synchronous shaft.

The risk of excessively high closure pressure adjustment is further minimised in that the adjustment means can be controlled in accordance with the closure pressure by means of the control unit.

According to a development of the invention, the stroke positions of the shaping tools or an adjustment position of the adjustment means correlating to the stroke position can be used as a reference value for controlling the tool unit in a subsequent workpiece shaping operation because all the radial dimensions of the product to be produced by the workpiece shaping operation are defined in relation to the closure point. The reference value can advantageously automatically be transferred to a machine control of the rotary swaging machine.

The measuring device and/or the control device is/are preferably an integral component of a machine control of a rotary swaging unit or is/are incorporated thereby.

According to the invention, the tool unit can further preferably be in the form of an external, internal or double rotor, in particular a counter-rotor, in accordance with the requirements placed on it.

The invention is explained in greater detail below with reference to an embodiment illustrated in the drawings, in which:

FIG. 1 is a perspective view of a tool unit of a rotary swaging machine which is illustrated as a cutout;

FIG. 2 is a schematic front view of a swaging mechanism of a tool unit which corresponds to FIG. 1 and which has four shaping tools which are in a closed position; and

FIG. 3 is a schematic section of the swaging mechanism which is shown in FIG. 2 and which has a workpiece arranged between the shaping tools.

FIG. 1 shows a tool unit, which is generally designated 10, of a rotary swaging machine 12 which is reproduced only as a cutout for shaping workpieces which are preferably rod-like or pipe-like. The tool unit 10 has a housing 14 having an introduction opening 16, which is arranged at, the front side, for conveying the workpieces to be shaped along an operating axis designated 18. The housing 14 surrounds a swaging mechanism 20 which is reproduced in greater detail in FIG. 2 and which has a plurality of shaping tools 22 which are arranged around the operating axis 18. The shaping tools 22 are guided together with swaging rams 24 in radial recesses 26 of a tool holder 28 in the form of a swaging mechanism head and can be driven radially relative to the operating axis 18 with a stroke movement by means of a tool drive 30 (FIG. 1).

An external ring 32 which is arranged concentrically relative to the tool holder 28 engages round the tool holder 28 and thus forms with the tool holder 28 an annular space 34, in which pressure members 36 in the form of rollers are arranged.

The tool unit 10 is in the form of an external rotor in the embodiment shown here, that is to say, the external ring 32 can be driven so as to rotate by the tool drive 30 (FIG. 1) relative to the tool holder 28. The swaging rams 24 project into a rotation path of the pressure members 36 which are also moved by the external ring 32 being rotated and are moved radially inwards in the case of radial alignment with a pressure member 36, as shown in FIG. 2, by the pressure member in the direction towards the operating axis 18 and thereby press the shaping tools 22 intermittently radially in the direction towards the operating axis 18. The shaping tools 22 thereby apply, to a workpiece which is introduced along the operating axis 18 between the shaping tools 22, a pressure pulse, each of which is directed counter to the other and by which the workpiece is shaped. The number of strokes of the driven shaping tools 22 can be several thousand strokes per minute during the shaping operation.

The tool unit 10 has a plurality of adjustment means 38 in the form of adjustment wedges in order to adjust the stroke position of the shaping tools 22 in a radial direction relative to the operating axis 18. The stroke positions of the shaping tools 22 can be adjusted by means of the adjustment means 38 so that the shaping tools 22 abut each other when the shaping tools 22 are in a closed state, as shown in FIG. 2, the closure point explained in the introduction, with a closure pressure which is dependent on the stroke position adjusted.

As is evident from FIG. 2, the shaping tools abut each other at the closure point not with the operating faces thereof at the workpiece side but instead with the mutually facing lateral faces thereof, the so-called upper faces.

In the embodiment shown here, the adjustment means 38 are arranged so as to be longitudinally displaceable parallel with the operating axis 18 in the direction of the direction arrow which is designated 39 in the highly schematic illustration of FIG. 3. The adjustment means are arranged, as is particularly evident from FIG. 3, in a manner known per se between one of the shaping tools 22 and the swaging ram 24 which is associated with the shaping tool 22, respectively, and are guided in axial recesses of the tool holder 28 (not shown). The adjustment means 38 are further arranged with the end thereof remote from the introduction opening 16 on a synchronous shaft, which is not illustrated in greater detail in the drawings, and can thereby be axially displaced together.

The tool unit 10 further has, according to the invention, a measuring device 40 which, in order to establish electrical power consumption of the tool drive 30, detects an input current of the tool drive 30 and an operating voltage applied to the tool drive 30 during driving of the external ring 32 or the shaping tools 22.

The power consumption of the tool drive 30 is proportional to the closure pressure of the shaping tools 22 derived from a drive torque of the tool drive so that the closure pressure resulting in the adjusted stroke positions of the shaping tools 22 at the closure point of the shaping tools 22 can be verified or established by a control unit 42 shown in FIG. 1 by means of the established power consumption of the tool drive.

The control unit 42 verifies the closure pressure in relation to a closure pressure desired value, which can be predetermined by means of the control unit 42, by means of a characteristic line which is defined in the control unit 42 and from which the relationship between the power consumption of the tool drive 30 and the closure pressure is apparent. Characteristic lines are stored in the control unit in this regard for various shaping tools 22 or combinations of swaging rams 24 and shaping tools 22.

The adjustment means 38 (FIG. 2) can be controlled in accordance with the desired value setting by means of the control unit 42 with regard to the displacement or displacement position thereof.

In order to verify the closure pressure, the tool unit 10 further has an operating mode for the tool device 1.0 selectable via the control unit 44 in order to verify the closure pressure. In that operating mode, the rotating tools 22 can be driven with a number of strokes that is smaller than the numbers of strokes used for the shaping operations.

The stroke positions of the shaping tools 22 adjusted in accordance with the desired value setting of the closure pressure, that is to say, the axial position of the synchronous shaft correlating to the adjusted stroke positions, can automatically be transferred by the control unit 42 to a machine control 44 of the rotary swaging machine 12 as a reference value for, controlling the subsequent workpiece shaping operations, by means of which radial dimensions of a shaping product to be produced can be defined.

According to the invention, the tool unit 10 can also be in the form of an internal or double rotor, in particular a counter-rotor, in accordance with the requirements placed thereon.

Verifying the closure pressure of the shaping tools 22 is briefly indicated below in accordance with the adjustment of the stroke positions of the shaping tools 22 or during the setup of a tool unit 10 according to FIGS. 1 to 3.

After the tool unit 10 has been provided with shaping tools 22 necessary for the shaping operation, a desired value of the closure pressure of the shaping tools 22 at the closure point of the shaping tools 22 or a parameter correlating to the closure pressure is predetermined via the control unit 42.

In a second step, an operating mode of the tool unit 10 provided for controlling the closure pressure is selected by means of the control unit 42 in order to verify the closure pressure, whereby the external ring 32 is subjected to a relative (slow) rotational movement for verifying the closure pressure via the tool drive 30, during which movement it is possible to establish the power consumption of the tool drive, that is to say, to detect the input current and the applied operating voltage, and possible risks of overloading the tool unit 10 are minimised. The stroke position of the shaping tools 22 is not yet adjusted at this time in the direction towards the operating axis 18, that is to say, the shaping tools 22 are not yet in a closed state at this time.

The adjustment means 38 are controlled by the control unit 44 via the synchronous shaft (not shown) in such a manner that the adjustment means 38 are adjusted in the direction towards the operating axis 18 in a continuous or stepped manner by means of the synchronous shaft in order to adjust the stroke position of the shaping tools 22. In this case, the adjustment means 38 are displaced for this purpose in the direction towards the introduction opening 16 of the housing 14 (FIG. 1) of the tool unit 10, the input current and the operating voltage of the tool drive 30 being measured by means of the measuring device 40, with the external ring 32 simultaneously being rotated, and the power consumption of the tool drive 30 being determined from those parameters.

In order to verify the closure pressure of the shaping tools 22, the tool drive power consumption established from the input current and the operating voltage of the tool drive 30 is compared with the closure pressure desired value on the basis of the characteristic line defined in the control unit 44. When a power consumption of the tool drive 30 correlating to the predetermined closure pressure desired value is reached, the adjustment of the adjustment means 38 at the closure point of the shaping tools and therefore the adjustment of the stroke positions of the shaping tools 22 is stopped.

The adjustment position of the adjustment means 38 or the synchronous shaft at the stroke positions of the shaping tools defined in that manner are automatically transferred to the machine control 44 of the rotary swaging machine 12 as a reference value for controlling subsequent workpiece shaping operations. 

1. Tool unit (10) of a rotary swaging machine (12) for shaping preferably rod-like or pipe-like workpieces, having a plurality of shaping tools (22) which are arranged about an operating axis (1) and which can be driven radially relative to the operating axis (18) with a stroke movement by means of a tool drive (30), and having adjustment means (38), by which stroke positions of the shaping tools (22) are adjustable in such a manner that the shaping tools (22) abut each other with a closing pressure which is dependent on the stroke positions adjusted when the shaping tools (22) are in a closed state, characterised in that there is provided a measuring device (40) for measuring a parameter, by means of which the closure pressure produced at the adjusted stroke positions of the shaping tools (22) can be verified.
 2. Tool unit according to claim 1, characterised in that a control unit (42) is provided for closure pressure control, it being possible to process the measured parameter for verifying the closure pressure by means of the control unit (42), in particular in relation to a desired range or desired value setting.
 3. Tool unit according to either claim 1, characterised in that there is provided in order to verify the closure pressure an operating mode of the tool unit (10), which can be selected via a control unit (42) for controlling the closure pressure.
 4. Tool unit according to claim 1, characterised in that the tool drive (30) is provided in order to produce a relative rotational movement of a tool holder (28) and an external ring (32) which engages round the tool holder (28).
 5. Tool unit according to claim 1, characterised in that the measuring device (40) is provided for measuring a parameter, y means of which a drive torque for driving the shaping tools (22) can be established.
 6. Tool unit according to claim 1, characterised in that the measuring device (40) is provided for measuring a consumption of electrical current of the tool drive (30) when the shaping tools (22) are driven.
 7. Tool unit according to claim 2, characterised in that the closure pressure can be determined by the control unit (42) using a characteristic line, which is preferably defined in the control unit (42), for the measured parameter or a characteristic value of the tool drive determined from the parameter and the closure pressure.
 8. Tool unit according to claim 1, characterised in that the adjustment means (38) are in the form of a plurality of adjustment wedges which are preferably guided between the shaping tools (22) and swaging rams (24) associated therewith and which are arranged parallel with the operating axis (18), the adjustment wedges being longitudinally displaceable in the direction towards the operating axis (18) relative to the shaping tools (22) in order to adjust the stroke positions of the shaping tools (22).
 9. Tool unit according to claim 2, characterised in that the adjustment means (38) can be controlled in accordance with the closure pressure by means of the control unit (42).
 10. Tool unit according to claim 1, characterised in that the stroke position of the shaping tools (22) or an adjustment position of the adjustment means (38) correlating to the stroke position can be used as a reference value for controlling workpiece shaping operations.
 11. Tool unit according to claim 1, characterised in that the tool unit (10) is in the form of an external, internal or double rotor, in particular a counter-rotor.
 12. Method for adjusting a tool unit according to claim 1, wherein there is verified by means of a measuring device (40) a closure pressure which is produced from the adjusted stroke position of the shaping tools (10) at the closure point thereof.
 13. Method according to claim 12, characterised in that the closure pressure is verified during driving of the shaping tools and simultaneous adjustment of the stroke positions of the shaping tools. 